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Effect of the interplanetary magnetic field Y component on the high‐latitude nightside convection
Author(s) -
de la Beaujardière O.,
Wickwar V. B.,
Kelly J. D.,
King J. H.
Publication year - 1985
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl012i007p00461
Subject(s) - midnight , interplanetary magnetic field , dusk , convection , polar , geophysics , latitude , physics , convection cell , geology , interplanetary spaceflight , solar wind , magnetic field , astrophysics , astronomy , meteorology , natural convection , quantum mechanics , combined forced and natural convection
Sondrestrom radar observations reveal that the dawn‐dusk (B y ) component of the interplanetary magnetic field (IMF) strongly influences the nightside polar convection. This effect is quite complex. The convection for one orientation of B y is not the mirror image of the other orientation. A positive B y (i.e., pointing toward dusk) seems to organize the velocities such that, at all local times, they are predominantly westward within the radar field‐of‐view (≃68°‐to‐82° invariant latitude). Between dusk and midnight, on one such occasion, sunward flow is observed within the polar cap. In the midnight and dawn sectors, when B y is negative, the plasma velocities often appear random. For large negative B y , the afternoon cell appears shifted toward early hours such that large southward velocities are observed about 3 hours before midnight. These are the only times when the predominant velocity component is southward.